In the driver side second bay, behind a drop down panel, I found the Transmisson Control. Found a 24/12 VDC Converter, an Electronic Control Unit (ECU), three relays, (Check Transmission, Retarder, Reverse), three 5 amp fuses (all check okay with an ohm meter), a test light, test switch, (which doesn't seem to lite the test light), an hour meter, and a 5 stud block, with black wires on 1,2,3.

The first thing I need to determine is do I in fact have 12 vdc out of the converter. Does anyone have a drawing of this, or the same unit?

Bill, make sure you have 12 volt output on terminals 4,5,6,7 of the 24 volt converter. You are doing a fine job so far. You'll get to the end of the tunnel.Here's a breakdown of what these wires do:Term 4 - 12v for ECU memoryTerm 5 - 12v Battery power to ECUTerm 6 - 12v Battery power to ECU and shift selectorTerm 7 - 12v Battery power (switched) and to Term H of the data connector.The Data Connector might be at bottom of shift tower, might have a spring loaded metal cover on it. This is where a ProLink will hook up.Let us know your results.

Bill, has any work been done recently around the shift tower, or bus wiring? What did you work on from the time you parked the coach and the time you tried to move it? I've seen the cannon plugs fall out of the backside of the shift pad. Also seen wiring disturbed and fail. It was about to fail anyway. That would not affect the voltage readings. But a CEL for the transmission would set. If you are not getting a transmission light, something's not powered up. Sammy's going to get you fixed up! And Ron, Vanner recommends that nothing but the battery leads be attached to the Vanner terminals. I doubt any harm would come from attaching leads to the Vanner, but it may confuse the Vanner causing an overcharge condition on one of your batteries (the rear battery). The 12V source for your transmission is the center 12V post on the rear battery. Same for the 12V headlight backup lead. Sammy, if you're passing out your phone number I'd love to have it!! You one smart guy! My bus is gonna crap somewhere one of these days and I want someone that knows some $#i+! You know your stuff. Very nice! Bill, feel free to call if you have a question regarding anything other than that ATEC transmission. I'll talk about that too, but I'm not versed on the unit as Sammy is. I do ex-NJTs and that's all I understand. DDEC and ATEC 748s. That's it. I'd definitely want to know what fixes this thing.

JR704 650 0235 anytime.

Logged

JR Lynch , Charlotte, NC87 MC9, 6V92TA DDEC, HT748R ATEC

"Every government interference in the economy consists of giving an unearned benefit, extorted by force, to some men at the expense of others.”

Bill, try this....J2 connector (black one) of trans ECU:Pin 3 - wire 203 - 12v memory - fed by term 4 of converter - might be a red wirePin 8 - wire 208 - 12v battery power - fed by term 5 of converter - might be a Blk/Grn wirePin L - wire223a - 12v battery power - fed by term 6 of converter - might be a grey/Red wirePin 2 - wire 202a - 12v switched battery power - fed by term 7 of converter - might be a Red/White wireI do not have a electrical diagram of your coach to see how Allison wiring integrates into it.For instance: There is a switched 24v source of power going to Fuse 3 - a 5 amp fuse or breaker.It then goes into the 24 v converter on term 3 - a 24v input.It is the only switched 24v input - as per the Allison diagram.Maybe it becomes the 12v output on term 7 of the converter - a switched 12v output.Maybe it becomes wire 202a, on pin 2 of the J2 connector of the ECU, telling the ECU to turn on.Diagram shows no internal wiring of 24v converter.Let me know if you need a picture of J2 and pin locations.Sammy

Sorry about all these postings. But Bill, do you have a kneeling valve on your bus? Its a switch in the LH side dash on top. Next to the air lock switch. If you have a kneeler, the trans won't shift at all with the kneeling function is deployed. Just another thought! JR

Logged

JR Lynch , Charlotte, NC87 MC9, 6V92TA DDEC, HT748R ATEC

"Every government interference in the economy consists of giving an unearned benefit, extorted by force, to some men at the expense of others.”

Do you have a DDEC engine? And does your motor stay running for a reasonable amount of time? The reason I'm asking is when you have a fault code the DDEC will not let the fast idle work and then will shut down your engine, might take ten minutes. I don't know if it works the same for your ATEC. You may want to get someone with a hand reader to check your tranny for fault codes.

Before I get flamed - just as a pleasant reminder - disconnect the ATEC from its power source for a 10 minute period - when reconnected shift to neutral - if you can't get a neutral indication see ATEC trouble shooting guide - HTH

Looks like the problem is with power to the ECU and shift selector. Can you provide a point inside the converter box to double check voltage or,,,,, on the inside of the converter, looking at the back of the plug, what color wires may be pins 8 and L?

No work has been done since my last move, wiring or otherwise.

Engine not effected, engine will run more than 10 minutes.

HTH, Please explain diconnect ATEL from power source. Could this act as a reset perhaps? Where do I find an ATEC trouble shooting guide?

Bill, go on the back of the converter, pins 5 and 6, see if you have an output.Might have open circuit between converter and ECU.Check battery cable connections - remove and clean all of them.I need a diagram of your bus, will try without it , would possibly help.I'll check back a little later...You're doing great so far, really.Sammy